first commit

app_vue/node_modules/thunky/README.md

@@ -0,0 +1,97 @@
+# thunky
+
+Delay the evaluation of a paramless async function and cache the result (see [thunk](http://en.wikipedia.org/wiki/Thunk_%28functional_programming%29)).
+
+```
+npm install thunky
+```
+
+[![build status](http://img.shields.io/travis/mafintosh/thunky.svg?style=flat)](http://travis-ci.org/mafintosh/thunky)
+
+## Example
+
+Let's make a simple function that returns a random number 1 second after it is called for the first time
+
+``` js
+var thunky = require('thunky')
+
+var test = thunky(function (callback) { // the inner function should only accept a callback
+  console.log('waiting 1s and returning random number')
+  setTimeout(function () {
+    callback(Math.random())
+  }, 1000)
+})
+
+test(function (num) {  // inner function is called the first time we call test
+  console.log(num) // prints random number
+})
+
+test(function (num) {  // subsequent calls waits for the first call to finish and return the same value
+  console.log(num) // prints the same random number as above
+})
+```
+
+## Lazy evaluation
+
+Thunky makes it easy to implement a lazy evaluation pattern.
+
+``` js
+var getDb = thunky(function (callback) {
+  db.open(myConnectionString, callback)
+})
+
+var queryDb = function (query, callback) {
+  getDb(function (err, db) {
+    if (err) return callback(err)
+    db.query(query, callback)
+  })
+}
+
+queryDb('some query', function (err, result) { ... } )
+
+queryDb('some other query', function (err, result) { ... } )
+```
+
+The first time `getDb` is called it will try do open a connection to the database.
+Any subsequent calls will just wait for the first call to complete and then call your callback.
+
+A nice property of this pattern is that it *easily* allows us to pass any error caused by `getDb` to the `queryDb` callback.
+
+## Error → No caching
+
+If the thunk callback is called with an `Error` object as the first argument it will not cache the result
+
+``` js
+var fails = thunky(function (callback) {
+  console.log('returning an error')
+  callback(new Error('bad stuff'))
+})
+
+fails(function (err) { // inner function is called
+  console.log(err)
+});
+
+fails(function (err) { // inner function is called again as it returned an error before
+  console.log(err)
+})
+```
+
+## Promise version
+
+A promise version is available as well
+
+``` js
+var thunkyp = require('thunky/promise')
+
+var ready = thunkyp(async function () {
+  // ... do async stuff
+  return 42
+})
+
+// same semantics as the callback version
+await ready()
+```
+
+## License
+
+MIT